KR102302227B1 - Method for signal reconstruction - Google Patents

Abstract

The present invention relates to a method for acquiring a Nyquist communication signal, and more particularly, to a signal compression unit for receiving an analog signal, generating aliasing to perform compression sampling, and generating a compressed sample signal; and a signal reconstruction unit for reconstructing the compressed sample signal.

Description

Nyquist communication signal acquisition method {METHOD FOR SIGNAL RECONSTRUCTION}

The present invention relates to a method for acquiring a Nyquist communication signal, and more particularly, to reduce the number of analog channels and the sampling rate by compressing the mixed spectrum once again by inducing intentional signal aliasing in a simple and analog-to-digital converter. It relates to a method for acquiring a Nyquist communication signal that enables

Applications of Electronic Warfare (EW) systems, Electronic Intelligence (ELINT) systems or cognitive radio communications require observing a multi-frequency signal, i.e., a set of multiple narrow-band signals with different center frequencies. . The Nyquist sampling rate is twice the widest maximum frequency. If a multiband signal is sparse, i.e. consists of a few narrow bands, the signal can be sampled without loss of information at a sub-Nyquist rate much lower than the Nyquist rate. have. The theoretical lower limit of the rate required for lossless sub-Nyquist sampling is the sum of the bandwidths, referred to as the 'Landau rate', if the spectral positions of all narrowband signals are known. On the other hand, if the spectral position is unknown, its lower limit is doubled.

A typical modulated wideband converter (MWC) may be a lossless sub-Nyquist sampler that aims to achieve a theoretical lower limit of the sampling rate. In this case, the MWC uses a pseudo-random signal (PRS) that periodically outputs a pulsed pattern. The MWC has multiple analog channels, each sequentially a PRS generator, a signal mixer, a low-pass filter (LPF) for anti-aliasing and a low-speed analog-to-digital converter (analog-to-digital converter). -digital converter, ADC). The system utilizes high-speed oscillating PRS and LPF to compress multi-band spectra and then sample at a sub-Nyquist rate. The reconstruction of the input multi-band spectrum is guaranteed under some conditions of compressed sensing (CS) theory. By the CS reconstruction algorithm developed for MWC, it has been demonstrated that MWC can achieve a theoretical lower limit of the lossless sub-Nyquist sampling rate.

In the MWC for this lossless sub-Nyquist sampling, the ADC follows an anti-aliasing rule, that is, f _s ≥ W _LPF . This general rule is for lossless sub-Nyquist sampling enough for

However, MWC relying on this high-end PRS generator is the only spectral compressor to achieve the lower limit of the lossless sub-Nyquist sampling rate. The ratio of spectral compression is entirely dependent on the oscillation speed and the length of the pulsed pattern within a single period of the PRS. In particular, in order to improve a compression ratio for a narrower multi-band signal, a PRS having a longer pattern length is required. Also, for lossless compression, the vibration rate must be higher than the Nyquist rate. Unfortunately, increasing the pattern length of a PRS generator with a switching speed in the tens of GHz range leads to difficult research problems such as high power consumption and large process area due to high chip speed in the field of chip engineering. impede the possibility

Therefore, there is a need to develop a technique for reducing the rate for lossless sub-Nyquist sampling of MWC close to the theoretical lower limit without upgrading the PRS generator.

Accordingly, the present invention has been proposed to solve the above problems, and by inducing intentional signal aliasing in the analog-to-digital converter to compress the mixed spectrum once again, so that the number of analog channels and the sampling rate can be reduced. An object of the present invention is to provide a method for acquiring a Nyquist communication signal.

Objects of the present invention are not limited to those mentioned above, and other objects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description.

A method for obtaining a Nyquist communication signal according to the present invention for achieving the above object includes the steps of: receiving an analog signal, generating an aliasing signal to perform compression sampling, and generating a compressed sample signal; and reconstructing the compressed sample signal.

According to the present invention, the number of analog channels and the sampling rate can be reduced by once again compressing the mixed spectrum by inducing intentional signal aliasing in the analog-to-digital converter.

Effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

1 is a diagram illustrating sampling efficiency in a relationship between a maximum bandwidth B and a division period f _{I. Referring to FIG.}
2 is a diagram for explaining a sampling system of a conventional MWC.
3 is a diagram for explaining a sampling system of the MWC according to an embodiment of the present invention.
4 is a diagram for explaining a principle of improving sampling efficiency by AMWC according to an embodiment of the present invention.
5 is a block diagram illustrating the configuration of an apparatus for obtaining a Nyquist communication signal according to an embodiment of the present invention.
6 is a flowchart illustrating a communication signal acquisition method in the signal compression unit of the Nyquist communication signal acquisition apparatus according to an embodiment of the present invention.

Objects and effects of the present invention, and technical configurations for achieving them will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. And the terms to be described later are terms defined in consideration of donation in the present invention, which may vary depending on the intention or custom of the user or operator.

However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. Only the present embodiments are provided so that the disclosure of the present invention is complete, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, the present invention is defined by the scope of the claims will only be Therefore, the definition should be made based on the content throughout this specification.

On the other hand, throughout the specification, when a certain part is "connected" with another part, it is not only "directly connected" but also "indirectly connected" with another member interposed therebetween. include In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

The input/output relationship of the conventional MWC (conventional MWC) following the anti-aliasing rule described above is described in M. Mishali and YC Eldar, "From theory to practice: Sub-nyquist sampling of sparse wideband analog signals," (IEEE J. Sel. Topics Signal Process., vol. 4, no. 2, pp. 375-391, Apr. 2010.). The input x ( t ) in the i- th channel is first mixed with Tp- periodic PRS p _i ( t ) which periodically outputs the sequence of the mixed chip L. By periodicity, the Fourier transform of p _i ( t ) is an impulse train. The FT of the mixed signal s _{i (} t ) = x ( t ) p _i ( t ) is a convolution of two spectra as shown in Equation 1 below.

<Equation 1>

에 대해 c _i,l 은 p _i (t)의 푸리에 급수 계수이고, 혼합 신호 s _{i (} t) 및 X(f-lf _p )는 LPH H(f)에 의해 필터링 된다. 이때, f ∈ F _LPF 에 대해 H(f) = 1이라 하고, 그렇지 않으면 H(f) = 0이고, 여기서

이다. 한편, X(f )는 F_NYQ에 의해 대역 제한되므로, 상기 <수학식 1>에서 무한 차수 합계는 하기 <수학식 2>와 같이 유한 차수로 감소한다.where l= -

C _{i, l} is the Fourier series coefficient of the p _i (t), mixed-signal s _{i (t)} and X (f _lf-p) for a is filtered by the LPH H (f). In this case, let H ( f ) = 1 for f ∈ F _LPF , otherwise H ( f ) = 0 , where

am. Meanwhile, since X ( f ) is _{band-limited by F NYQ} , the infinite order sum in Equation 1 is reduced to a finite order as shown in Equation 2 below.

<Equation 2>

에 의해 산출되고, q₀는

에 의해 산출된다. 다음으로, 레이트의 ADC f_s = T_s ¹는

의 샘플을 취한다. 일반적인 안티-에일리어싱 룰에 의해, f_{s =} W _LPF 라 한다. 이때, yi [n]의 이산 시간 푸리에 변환(Discrete-Time Fourier Transform, DTFT)는 상기 <수학식 2>의 스펙트럼을 보존한다.Here, L _O is

, and q ₀ is

is calculated by Next, the ADC f _s = T _s ¹ of the rate is

take a sample of By the general anti-aliasing rule, f _{s =} W _LPF . In this case, the Discrete-Time Fourier Transform (DTFT) of yi [ n] preserves the spectrum of Equation 2 above.

In Equation 2, since the bandwidth W _LPF is wider than the shifting period f _p , all subbands X( f lf _p ) are spectrally correlated with q−1 adjacent subbands. To make them spectrally orthogonal, sample yi [ n ] is modulated and low-pass filtered in parallel through q digital channels as shown in Equation 3 below.

<Equation 3>

s = -q0, . . . , for q0, where hf _p [ n ] is a digital LPF with a cut-off frequency of f _p/2. The DTFT of <Equation 3> is as shown in <Equation 4>.

<Equation 4>

이고, 대역폭은 쉬프팅 구간과 동일하기 때문에 상기 <수학식 4>에서 부대역 X(f lf _p )는 스펙트럼적으로 서로 직교한다. X(f)는 다중 대역 신호이기 때문에, 상기 <수학식 4>에서 몇 개의 부대역들만이 0이 아닌 값을 갖는다. 만약, f _p ≥ B이면, 구간 f _p 의 균일한 그리드(uniform grid)는 최대 두 개로 각 대역을 분할하기 때문에, 부대역들의 희박성 K에 대한 상한은 K ≤ 2K _B 이다.here,

, and since the bandwidth is the same as the shifting period, the subbands X( f lf _p ) in Equation 4 are spectrally orthogonal to each other. Since X ( f ) is a multi-band signal, only a few subbands in Equation 4 have non-zero values. If f _p ≥ B , since the uniform grid of the interval f _p divides each band into at most two, the upper limit for the sparseness K of the subbands is K ≤ 2K _B.

As a result, each analog channel outputs q different sequences, so cMWC gets the Mq equation for input reconstruction. Therefore, it has been proven that the input spectrum can be reconstructed according to the number of equations.

Previously, in order to obtain more equations for a given f _p for generating the PRS and an equation for a fixed number of channels M, cMWC increases the sampling rate f _s by controlling the channel-trading parameter q . should depend on

In Equation 4 above, the MWC divides the input spectrum into a plurality of subbands according to a uniform grid of division intervals, and then takes samples of the weighted sum of the subbands. In this case, the division interval is represented by f _l , and the division interval of cMWC f ₁ is the same as f _{p .} From the samples, finally the CS recovery algorithm recovers K non-zero subbands containing the split fragment _{of K B multibands.} As a result, a total sampling rate is spent taking the sample of the non-zero bandwidth of the K subbands f _l. This means that the total sampling rate required for lossless sampling by MWC is at least f _s,total ≥ 2 Kf _I , where a factor of 2 indicates that it arises from the unknown support of a non-zero subband. In contrast, for a typical sub-Nyquist sampling system, the minimum requirement for lossless sampling of a multiband signal is f _s,total ≥ 2 K _B B , where K _B B is the upper bound of the actual spectral occupancy of the multi-band signal. That is, when f _I is much larger than B, the MWC inefficiently consumes a fraction of the total sampling rate. Specifically, f _I greater than B has a higher probability that K non-zero subbands are composed of unused bands, ie, zeros. An inefficient use of the overall sampling rate is illustrated in FIG. 1 .

1 is a diagram illustrating sampling efficiency in a relationship between a maximum bandwidth B and a division period f _I. Specifically, (a) is a diagram for inefficient sampling, and (b) is a diagram for improved sampling efficiency is a drawing for

Ideally, when the division interval f _I satisfies f _I ≥ B and is finer and closer to B, the sampling efficiency is improved as shown in FIG. 1 . Its efficiency is Kf _I = K _B B , it is maximized. Based on this observation, the sampling efficiency α of the MWC is defined as the following <Equation 5> as the ratio between the actual spectrum occupancy of the multi-band band and the total bandwidth of the reconstructed subbands.

<Equation 5>

By definition of K, α ≤ 1 always holds.

Briefly , improving α has two advantages. First, for lossless sampling of a given multi-band signal, the required sampling rate f _s,total decreases to approach the theoretical minimum requirement f _s,total = 2K _{B B.} By definition, α is Closer to 1 indicates that a portion of f _s is inefficiently consumed taking samples of the unused band in FIG. 1 . According to the reduced f _s,total , the number of channels M or the number of channels M or the number of sampling rates f _s of the ADC in each channel is reduced. Second, for a given and fixed f _s,total , we show that improving α yields a more independent equation for signal reconstruction, so that more complex multi-band signals with higher K _{B can be perfectly recovered.}

2 is a diagram for explaining a sampling system of a conventional MWC.

Referring to FIG. 2 , the conventional MWC, ie, cMWC, consists of a plurality of channels. Each channel mixes the wideband received signal x ( t ) with p _i (t) , which is a PRS of period T _P , and then passes through a low-pass filter h(t) with a bandwidth of W _LPF and is sampled at a sampling interval of T _{s .} do. The maximum frequency of x ( t ) is f _max , and the spectrum consists of N non-overlapping narrowband spectra, and the bandwidth of each narrowband spectrum is B. W _LPF was set to have a relationship between f _p = T _p ^-1 , which is the repetition rate of PRS, and W _LPF = qf _p , and at this time, q = 3 was fixed. However, this is only an example and may be changed as necessary. The signal mixing process of MWC shuffles the spectrum of x ( t ) so that the spectrum information of the entire band exists in a modified form within a very narrow baseband. Then, the spectrum of x ( t ) is compressed by the low-pass filter taking only the modified form of spectral information existing in the baseband. Reconstruct the discrete spectrum of x ( t ) through the compressed spectrum. Conventional MWC, that is, cMWC, matches the sampling rate of f _s := T _s ^-1 and the pass bandwidth of h(t) , that is, f _s = W _LPF , so that aliasing of the compressed spectrum does not occur during the sampling process. prevented from happening.

For this cMWC, the sampling efficiency depends entirely on the hardware capabilities of the PRS generator, which can cause serious implementation problems. The sampling efficiency of _cMWC depends on the specifications of the PRS generator because f _I and cMWC are fixed at f _{p .} According to its definition, the only way to improve the sampling efficiency α _cMWC of cMWC was to bring the repetition rate f _{p of PRSs close to B.}

As previously discussed, the chip speed of PRS is _{dependent on the} Nyquist rate, that is, f _c ≥ f NYQ. should be more than Therefore, f _p = f _c L ^{1 ,} the chip length L is the only free parameter controlling f _{P .} Since B is usually much smaller than f _NYQ , we need a very long L to fit _{f p closer to B.} Specifically, in order to sample without loss of information, cMWC shows that the oscillation rate of the PRS is the Nyquist rate of x ( t ), f _NYQ. := must be faster than 2fmax , and the closer the value of f _p is to the value of B, the lower the sampling rate is required. The value of f _p is possible by adjusting the length of the pseudo noise pattern of the PRS. if, If f _NYQ is very large while B is very small, then In order for f _p to be equal to B, the PRS must have a very long pseudo-noise pattern. However, it is difficult to commercialize such a PRS generator because it consumes a lot of power and requires a large process area. Therefore, other means of improving α that do not depend on the chip length L of the PRS are very important.

The present invention proposes another method capable of obtaining more equations and improving the input reconstruction performance without a cost-intensive method of increasing the total sampling rate f _s (total = Mfs ) or decreasing f _{p .} Specifically, it is intended to improve sampling efficiency α with fixed standards f _p , f _{c and L given for PRS generation.} At this time, small L and B and large f _NYQ are assumed, which means that f _p is sufficiently large compared to B, and makes room for improvement of α. That is, for a natural number p > 1, f _p ≥ pB . Then α can be improved without upgrading the PRS generator and without introducing implementation issues such as higher power consumption and larger process area.

로 설정하며, p=2로 설정하기로 한다. AMWC는 샘플링 과정에서 에릴리어싱 현상을 허용함으로써 cMWC에서 PRS의 f _p 의 값을 줄이는 어려운 방법과 동일한 효과를 가져온다. 에일리어싱 현상으로 인해 cMWC와는 그 입-출력 관계식은 다르게 변형된다.Hereinafter, the method proposed by the present invention will be referred to as AMWC (Aliased Modulated Wideband Converters). This AMWC renders the anti-aliasing rule f _s = W _LPF used in cMWC unnecessarily. Instead AMWC is to generate an aliasing at the ADC is by the process of sampling x (t) spectrum, that is, to improve the α induced without relying on the specification of the division intervals regulate f _l, and PRS. For this, the new sampling rate

, and p = 2 is set. AMWC has the same effect as the difficult method of reducing the value of f _p of PRS in cMWC by allowing aliasing phenomenon in the sampling process. Due to the aliasing phenomenon, the input-output relation is transformed differently from cMWC.

3 is a diagram illustrating a signal processing process according to the sampling system of the MWC according to an embodiment of the present invention.

Referring to FIG. 3 , the MWC, ie, the AMWC, according to an embodiment of the present invention is configured in parallel with M analog channels, and each channel is a PRS generator, a signal mixer, and a low-pass filter for anti-aliasing. It consists of a low-pass filter (LPF) and a low-speed analog-to-digital converter (ADC).

Here, pseudo-random generating a pseudo-random signal

, PRS의 반복률은

로 표시한다. LPF는 컷-오프 주파수

를 가지며, 여기서 W _LPF 는 음의 주파수를 포함하는 필터의 대역폭을 나타낸다. LPF 대역폭은

로 설정되며, 여기서 q는 홀수 양의 정수인 채널 트레이딩 파라미터이다. 마지막으로, 모든 채널에서 동일한 샘플링 레이트는 f _s 로 나타낸다. 모든 채널의 샘플링 레이트를 합한 총 샘플링 레이트는

로 정의된다.Each PRS for channel index i _i ( t ) is periodic and outputs chips of odd length L within a single period Tp. Each chip has a chip period T _c = T _p L ^-1 lasts for a while the chip speed

, the repetition rate of PRS is

indicated as LPF is the cut-off frequency

, where W _LPF represents the bandwidth of the filter including the negative frequency. LPF bandwidth is

, where q is an odd positive integer channel trading parameter. Finally, the same sampling rate for all channels is denoted by f _{s .} The total sampling rate is the sum of the sampling rates of all channels.

is defined as

This AMWC first compresses the input multi-band spectrum using PRS, and then the non-zero sub-bands of the multi-band spectrum are recovered by the CS recovery algorithm. In order to succeed in CS recovery, all spectral components within the Nyquist range F _NYQ of each PRS must be independent, and a fast chip speed requires f _c ≥ f _NYQ . Let f _c = f _NYQ be set.

Compared to the cMWC described above, it is designed not to meet the anti-aliasing rules. Rather, it is designed to induce intentional aliasing by setting the bandwidth of the LPF to be larger than the sampling rate. In fact, in both cMWC and AMWC, aliasing is first introduced by the mixer. The effect of this first aliasing is the same as in Equation 2 above, where the mixer moves, weights, and the signal spectrum X ( f ) overlaps its moving version with an interval of f _{p .}

By the second aliasing, the overlapped spectra are aliased again with an interval of a new sampling rate AMWC f' _{s smaller than the filter bandwidth.} By adjusting the relationship between f _p and f' _s , the division interval f _l , the interval at which X ( f ) is separated from the output of the AMWC, is adjusted. The new sampling rate f' _s of the AMWC is expressed in Equation 6 below.

<Equation 6>

Here, q' is the new channel trading parameter and odd number of AMWC. The bandwidth of _LPF is W LPF = q'f _p , and thus W _LPF = pf' _s for the integer aliasing parameter p > 1.

In order to ensure that there is no loss of information in X( f ), we need to show coprime p and q' where q' > p. The new sampling rate introduces additional aliasing and adjusts the splitting interval f _l to improve the sampling efficiency.

AMWC divided interval, that _{is, f l, AMWC = f '} p LCS (least common shifting interval) to be the same as for <Equation 7>.

<Equation 7>

Meanwhile, since X ( f ) is divided into spectrally orthogonal subbands at intervals of f′ _p , that is, the division interval of AMWC is p times lower than f _l,cMWC LCS according to Equation 7 above. is the same as f _'p.

On the other hand, as a new sampling rate f' _s is introduced in Equation (6), it becomes easier to compare AMWC and cMWC. Specifically, if the sampling rate is fixed, the number of equations for the input reconstruction obtained by cMWC can be compared with the number of equations obtained from the AMWC, and the sampling rate for the two can be compared with the fixed number of equations. have.

For a given sampling rate f' _{s =} q'f _p /p , the number of equations obtained in AMWC is Mq' . For a given sampling rate f _{s =} qf _p , the number of equations obtained in cMWC is Mq . If the sampling rate remains the same, i.e. fs = f's, then q' = qp . This means that AMWC has p times more equations than cMWC. Table 1 below shows an example of an increase in the number of equations in AMWC, and is a parameter comparison table between AMWC and cMWC.

<Table 1>

On the other hand, by fixing the number of equations, when Mq = Mq' , AMWC requires a sampling rate p times smaller than cMWC.

4 is a diagram for explaining a principle of improving sampling efficiency by an AMWC according to an embodiment of the present invention, and is a diagram for explaining how the AMWC adjusts a division interval and improves sampling efficiency. In this case, a case where q = 3, q' = q , p = 2, M = 3 is illustrated.

Specifically, (a) is a diagram for comparing spectral processing processes between cMWC and AMWC, and (b) is a diagram illustrating an output relationship between cMWC and AMWC. First, the input spectrum X ( f ) is mixed with the PRS and aliased by filtering through the LPF. Here, the aliased version of X ( f ) is denoted by Yi ( f ), and the main difference between cMWC and AMWC is how the time-sample of this Yi ( f) is taken. As seen through (a), the cMWC prevents the spectrum Yi ( f ) from being aliased in taking time-samples, whereas the AMWC deliberately aliases the spectrum Yi ( f ) once again. Accordingly, there is a difference between the output relationship of cMWC and AMWC, and the difference can be confirmed through (b).

Meanwhile, (c) is a diagram illustrating the input-output relationship of cMWC, and (d) is a diagram illustrating the input-output relationship of AMWC. As in (c), the split interval of cMWC is f _p , whereas that of AMWC as in (d) is halved with f' _{p .} That is, the sampling efficiency of AMWC is doubled ( p = 2).

Hereinafter, this sampling efficiency will be described. That is, as defined in the <Equation 5>, it compares the sampling efficiency of the AMWC (α _AMWC) and the sampling efficiency of the _cMWC (α cMWC).

In general, the sampling efficiency of a rare (Sparsity) K function random variable, and group indicate a scarcity of cMWC and AMWC respectively K and K _{cMWC AMWC,} for K and K _{cMWC AMWC} In all cMWC and AMWC X (f) of the band K _B are both a sub-band, that is, it is assumed to occupy _cMWC K = K = K _{B AMWC.} This occurs with a high probability when f _p p ^-1 >> B, and the center frequencies of multiple bands are sufficiently far apart from each other _{by a small K B .}

Under this assumption, the sampling efficiencies of cMWC and AMWC are obtained by the following <Equation 8> and <Equation 9>, respectively.

<Equation 8>

<Equation 9>

If, if p = 1, and cMWC AMWC because exactly the same, α and α _{cMWC AMWC} also becomes equal to (α = α _{cMWC AMWC).} On the other hand, if p > 1, the deliberate aliasing of AMWC improves the sampling efficiency in proportion to p.

5 is a block diagram illustrating the configuration of an apparatus for obtaining a Nyquist communication signal according to an embodiment of the present invention.

Referring to FIG. 5 , the Nyquist communication signal obtaining apparatus 1 includes a signal compressing unit 10 and a signal restoring unit 20 .

The signal compression unit receives an analog signal, generates aliasing and compresses and samples to generate a compressed sample signal. A pseudo-random signal generation unit 11, a mixer 12, a low-pass filter 13, and an analog-to-digital conversion unit (14) may be included.

The pseudo-random signal generator generates a pseudo-random signal, and the mixer mixes the analog signal received from each of the plurality of analog channels with the pseudo-random signal to generate a mixed signal. Meanwhile, the low-pass filter generates aliasing to generate an aliased mixed signal, and the analog-to-digital converter performs analog-to-digital conversion on the aliased signal.

Meanwhile, the signal restoration unit may include a band pass filter 21 , a modulator 22 , and a decimation 23 .

6 is a flowchart illustrating a communication signal acquisition method in the signal compression unit of the Nyquist communication signal acquisition apparatus according to an embodiment of the present invention.

Referring to FIG. 6 , upon receiving an analog signal (S601), a pseudo-random signal, that is, PRS, is mixed with the analog signal (S603), and the mixed signal is passed through a low-pass filter that generates aliasing to generate a sampling rate f ' _s to analog-digital conversion (S605). Thereby, a sampled signal, ie, a compressed sampled signal, is output from the plurality of analog channels.

Thereafter, a frequency is modulated through a band pass filter in a plurality of digital channels corresponding to each of the plurality of analog channels (S607), and output spectra output from each of the digital channels are combined to generate an output signal (S609). Accordingly, an input signal is determined based on the spectrum information of the output signal and the pseudo-random signal (S611).

As described above, the present invention relates to an aliased MWC that reduces the lossless sub-Nyquist sampling rate for a given PRS, breaking the conventional anti-aliasing rule and setting the bandwidth of the previous LPF to be larger than the ADC sampling rate. to induce intentional aliasing in the ADC of each spatial channel. First, in addition to the first spectral compression by the mixing and LPF process, this intentional aliasing leads to another spectral compression according to the specific relationship between the bandwidth of the previous LPF and the ADC sampling rate. Through two spectral compression procedures, the compression ratio is improved without a faster or longer PRS signal. That is, the present invention achieves the effect of improving sampling efficiency by reducing the lossless sub-Lyquist sampling rate without upgrading the PRS, and eliminating the need to additionally configure hardware.

In the present specification and drawings, preferred embodiments of the present invention have been disclosed, and although specific terms are used, these are only used in a general sense to easily explain the technical content of the present invention and help the understanding of the present invention. It is not intended to limit the scope. It will be apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims (4)

A method for acquiring a Nyquist communication signal, the method comprising:
receiving the analog signal, generating aliasing to perform compression sampling to generate a compressed sample signal; and
reconstructing the compressed sample signal;
generating a compressed sample signal by receiving the analog signal and compressing the sample by generating aliasing,
generating a pseudo-random signal by a pseudo-random signal generator;
mixing, by a mixer, the received analog signal on each of a plurality of analog channels with the pseudo-random signal to generate a mixed signal;
generating, by a low-pass filter, first aliasing to generate an aliased mixed signal;
After the analog-to-digital converter secondarily generates aliasing for the aliased signal using the sampling rate (f' _s ) according to Equation 10 below, analog-to-digital conversion is performed to obtain the compressed sample signal comprising the steps of creating
_{The bandwidth of the low-pass filter is set to be larger than the sampling rate (f' s} ) of the analog-to-digital converter, and is 1/q times the repetition rate of the pseudo-random signal, and the bandwidth of the low-pass filter is > can be represented by the sampling rate (f _'s) is divided interval (f _{l, cMWC} or f in order to improve the sampling efficiency (α _AMWC)' by adjusting a _p), the division interval (f _'p) may be expressed by the following <Equation 12>, and the sampling efficiency may be expressed by the following <Equation 13>.
<Equation 10>

<Equation 11>
W _LPF = q'f _p
<Equation 12>

<Equation 13>

where f _p is the split interval, q' is the channel trading parameter but odd, B is the maximum bandwidth, and K _B B is the upper bound of the actual spectral share of the multi-band signal. delete delete delete

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